Our ADF molecular DFT code is a powerful tool for studying optical properties of nanoparticles, due to efficient and accurate treatment of relativity, making use of symmetry, fast TDDFT methods, and specialized exchange-correlation potentials. Advanced methods are available for environments and multi-level calculations.

Surface-enhanced Raman spectra (SERS), as well as hyper-Raman (SEHRS) and optical active (SEROA) spectra of molecules on large metallic nanoparticles are accessible through the DIM/QM methodology.

With DFTB and its time-dependent extension TDDFTB, spectroscopic and dynamical properties of very large nanoparticles such as quantum dots are possible, including excited state dynamics and charge transport with non-equilibrium Greens functions (NEGF).

DFTB has been extended by the recent GFN1-xTB method from Grimme, allowing for highly efficient quantum tight-binding calculations of all elements up to Z = 86.

ReaxFF has been used widely in nanotechnology. For example carbon nanotube formation, nanoparticle aggregation and Pd nanocatalysts under operating conditions with grand-canonical Monte Carlo (GCMC). With the latest force field fitting tools in the Amsterdam Modeling Suite, fitting ReaxFF parameters to the problem at hand becomes possible as described in the new Advanced Reparametrization Tutorial.

• Accurate treatment of relativistic effects with ZORA
• Molecular symmetry used efficiently in SCF and TDDFT
• State selective and core excitations
• DIM/QM for excited state properties of molecules on large metallic nanoparticles
• Frozen-density embedding for environment effects and large systems
• Use same basis sets for molecular and periodic DFT
• Insights from bonding analysis,
• Many spectroscopic properties (UV/VIS, XAS, NMR, …)
• Fast TDDFT methods and model potentials (SAOP, LB94)
• DFTB: 1000s of atoms, including fast TDDFTB
• ReaxFF: study the reactivity of up to millions of atoms
• GCMC for nanocatalysts under actual p,T conditions (see also advanced exercise)
• Transport properties with transfer integrals and NEGF

Try the Amsterdam Modeling Suite

The DIM/QM method for modeling plasmon-enhanced photochemical properties has recently been extended to several non-linear optical properties with damped cubic response theory. A recent paper by Zhongwei Hu and Lasse Jensen discusses the methods to simulate plasmon-enhanced two-photon absorption (PETPA) and applies this to para-nitroaniline. The coupling between the molecular excitations and the plasmon, treated with classical atomistic electrodynamics is very complex in this non-linear optical regime. The DIM/QM methods can provide insight in these complex couplings, in this case plasmon enhancement of a two-photon absorption dark state.

See the tutorial

Check out our advanced tutorial on how to fit ReaxFF force field parameters with the latest parametrization tools: ADFtrain and CMA-ES.

ReaxFF fitting tutorial